Now with the confidence of former No. 1 Lindsay Davenport by her side as a coach, the unseeded Keys on Saturday downed No. 4 seed and two-time Wimbledon champion Petra Kvitova 6-4 7-5 in the third round at the Australian Open.

“I felt, I don’t know,” Nadal said. “At the end of the first set, I start to feel my body very bad, very tired…I was worrying crazy. Then when I was serving for the third, almost throw up…I suffered too much on court for three hours and a half. I was suffering a lot. Too much. You know, was not funny today the way that the match was. Obviously is a very positive thing that finally have the chance to win, but, yeah, I hope to recover myself.”

“As always, I had the jitters going out in the first match of a Grand Slam,” Serena said. “It’s never super easy to be the one that everyone wants to beat. So I always have to be a little bit above. But yeah, I felt okay. I definitely think I can improve a tremendous amount though.”